Minor Traumatic Brain Injury
Mild TBI (MTBI) is one of the most common forms of brain injury. Mild TBI occurs when an impact or forceful motion of the head results in a brief alteration of mental status. This is in contrast to more severe TBI, which is associated with extended periods of unconsciousness, prolonged amnesia or penetrating skull injury. The CDC has recommended a definition for MTBI as an injury to the head as a result of blunt trauma or acceleration or deceleration forces that result in one or more of the following conditions: any period of observed or self-reported transient confusion, disorientation, or impaired consciousness; dysfunction of memory around the time of injury; loss of consciousness lasting less than 30 minutes; and observed signs of neurological or neuropsychological dysfunction such as seizure acutely following injury to the head. Among infants and very young children: irritability, lethargy or vomiting following head injury also met the CDC definition for MTBI (7).
Grades of Concussion
There is no standard classification system for concussions. Four of the leading researchers in head injuries maintain their own classification system. The symptoms of each degree of concussion are often very similar, and one can be confused when accessing a head injury.
Concussions can be divided into five grades:
Grade 0: results when the head is struck or moved rapidly. It is characterized by a post injury headache and difficulty with concentration. The athlete may not notice any other symptoms.
Grade 1: concussions occur in the same manner but the athlete may appear stunned or dazed. There is no loss of consciousness (LOC), and sensory difficulties clear in less than one minute. Grade 1 concussions are the typical I got my bell rung description from the athlete.
Grade 2: concussions are characterized by headache, cloudy senses lasting longer than one minute, and no LOC. The athlete may have other symptoms including, tinnitus, amnesia, irritability, confusion, or dizziness. One, all or none of these symptoms could be present.
Grade 3: concussions are characterized by LOC of less than one minute, the athlete will not be comatose, and exhibit the same symptoms as a grade 2 concussion.
Grade 4: concussions are characterized by LOC of greater than one minute. The athlete will not be comatose, and will also exhibit the symptoms of the grade 2 and 3 concussions.